This track has been raced on 4 configurations (The Circuit, 2.57 mi; 19, 2.92 mi; 1.83 mi; 3.02 mi). Laps on different configurations are not comparable, so only events on the 2.57 mile layout are shown; switch above to see the others.
One session is left out because the timing does not look like full laps: Cal Club 2023 Qualifying #2.
One run is left out as not that car's own laps (far quicker than the car managed in any other session and than anyone else in its class all week; usually a swapped transponder): Tom Burt in Cal Club 2025 PM (1:42.300; the car's best in any other session was 1:52.334 and the rest of the class's best all week 1:50.233).
One row per driver and car (a driver who changed cars has a row for each). Each cell is that driver's best in that car across the selected events, with the session it was set in. Best 5-lap stint is the mean of the driver's quickest five consecutive race laps, and consistency is how far their median race lap sat behind their best in that race (small is a driver who does it every lap); both come from the race with the best stint. The fastest in each column is purple, and a car whose best lap is more than 115% of the fastest in its class is greyed (marked ">115%" beside the driver) and left out of the colour scale. Click a column to sort, a row to highlight it.
Theoretical lap is the sum of the best sectors, whichever laps they came from, and never slower than the best lap (where a car's fastest laps were recorded without sector times, its best lap is used). The 115% mark is about the car's best lap only: a car whose best lap is within 115% of the fastest in its class is never marked. Greyed sectors with no theoretical lap mean the sector times on file do not add up to a believable lap. Letters refer to the events above; Q is qualifying, R a race.
Sectors
S1 SF → IM1 0.65 mi
S2 IM1 → IM2 0.75 mi
S3 IM2 → SF 1.17 mi
Spd In → Out 0.03 mi
Sectors are numbered in lap order from start/finish, whatever each event's timing called them; the loop names are SCCA timing's.
By car
Car
Class
Drivers
Lap
Qual
Race
Trap
S1
S2
S3
SCCA Ent SRF3
SRF3
38
1:50.233Caleb Shrader
1:50.233Caleb Shrader
1:50.825Caleb Shrader
138.9Paul Marino
30.136Caleb Shrader
31.672Caleb Shrader
44.841Tom Burt
Mazda RX-3
STU
1
1:50.913Tony Rivera
1:50.913Tony Rivera
1:52.737Tony Rivera
135.2Tony Rivera
30.415Tony Rivera
32.456Tony Rivera
47.999Tony Rivera
Mazda Miata
EP/STU
2
1:51.602Whitfield Gregg
1:59.603Joe Carr
1:59.157Joe Carr
131.6Joe Carr
30.652Whitfield Gregg
32.263Whitfield Gregg
48.687Whitfield Gregg
BMW M3
STU
1
1:52.380Wilson Powell
1:55.401Wilson Powell
1:53.843Wilson Powell
102.6Wilson Powell
30.577Wilson Powell
32.372Wilson Powell
49.215Wilson Powell
Mazda MX-5
EP/STU
4
1:53.088Glen McCready
1:53.088Glen McCready
1:53.487Glen McCready
125.9Dale Shoemaker
30.761Glen McCready
32.765Glen McCready
49.458Glen McCready
Honda S2000
STU
1
1:53.640Rylan Hazelton
1:55.834Rylan Hazelton
1:53.640Rylan Hazelton
134.8Rylan Hazelton
30.582Rylan Hazelton
32.779Rylan Hazelton
49.779Rylan Hazelton
Mazda RX-7
EP/STU
3
1:56.468Kurt Frietzsche
1:56.468Kurt Frietzsche
1:56.573Kurt Frietzsche
130.4Michael Lewis
31.324Kurt Frietzsche
33.891Brandon Droese
50.204Kurt Frietzsche
BMW 330
STU
1
1:56.492Sean Lovett
1:56.492Sean Lovett
1:57.049Sean Lovett
133.7Sean Lovett
31.816Sean Lovett
33.669Sean Lovett
50.941Sean Lovett
Nissan 300ZX
STU
1
1:59.183James Slechta
1:59.183James Slechta
2:00.458James Slechta
132.0James Slechta
32.882James Slechta
34.528James Slechta
51.773James Slechta
BMW E30
EP
1
2:00.712Sean Lovett
2:00.712Sean Lovett
2:01.864Sean Lovett
127.6Sean Lovett
32.761Sean Lovett
34.806Sean Lovett
53.058Sean Lovett
Porsche Boxster
EP
1
2:01.940William Robinson
2:01.940William Robinson
2:02.887William Robinson
130.6William Robinson
32.969William Robinson
35.257William Robinson
53.408William Robinson
The best any driver of each car managed across the selected events, with who set it. Spellings and model years of the same car are grouped; click a row marked ▸ to see each version. Grouping is worked out from the names, so tell us if two cars are wrongly merged or split.
Rule changes between these events
Cal Club 2023 → Cal Club 2024 2023-02-24 to 2024-02-23
slowerSRF Renault Alliance solid front rotors banned; restrictor reduced 35mm to 34mm for 2011+ Kawasaki; minimum weight increased to 1100 lbs for 2009+ stock engines.
As printed in Fastrack
In SRF, GCR section 9.1.8.D.X.g, change as follows: "Brakes: Hawk Blue 9012 pads P/N 801993 must be used. Wilwood vented rotor P/N 800065 shall be used as delivered with no machining of any kind. Minimum thickness 12.20mm (0.481"). The 1985 Renault Alliance solid front rotor (Reference: Bendix PRT1318 or Centrix 121.11004) may be used on front, rear, or both axles, but each axle must be paired to the same type rotor. The Renault Alliance solid front rotors may not be used. Rubber caliper bushings may be replaced with bronze bushings P/N 1196185 or P/N 1196185. Original caliper pistons may be replaced with vented caliper piston P/N 1196184; no other modification allowed. Wilwood caliper with bracket universal fit P/N 800038 may be used as delivered with no modification of any kind. Wilwood knock back spring (2.63 lbs.) P/N 800045 may be used as delivered with no modification of any kind;
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maximum of one spring per caliper." P2 Engine Table Spec Line Engine Series
A specification table follows in the original; it is not shown here.
wordingSRF3 tail sections allowed on SRFs with GEN3 airbox shimming up to 19 mm; alternate dash panel P/N 180100 or 180101 relocated in rules.
As printed in Fastrack
In Spec Racer Ford, GCR section 9.1.8.D.1.E, change as follows: "j. Optional Bodywork Modification: Viewing the tail section of the car from behind, draw a vertical line at the left and right ends of the outer vents from the bottom edge of the bodywork up to a point two (2) inches below the crease at the lower edge of the vented panel. Make a vertical cut at each line. The horizontal cut is to be one (1) inch below the crease at the base of the vented panel. Leave a one (1) inch radius at each corner. Air Scoop (P/N 190000) must be installed in conjunction with rear cutout per Enterprises installation instructions. SRF3 tail sections are allowed on SRFs. For purposes of tail section to center section fitment with the GEN3 airbox, shimming is allowed at the rear of the center section. Shim material may be up to 19 mm (0.75") thick along the 1" upper square sidepod
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tube. Mounting location cannot be modified or added. Shim material must be securely attached, but must not be welded. An alternate dash panel has been approved for use in Spec Racer Fords. The dash will be furnished by Enterprises only. P/N 180100 or 180101 k. Required Bodywork Modification: A 22.5" diameter wheel arch shall be cut in each side of the tail section. Viewing the tail section from the side, draw a vertical line at the drive axle centerline. Locate the top of the wheel arch at a point measured from the bottom edge of the tail section 9.25" vertically along the centerline. The 22.5" diameter circle intersects the bottom edge of the tail section 11.1" either side of the centerline. The tail section may be reinforced in the forward and aft portions of the wheel arch. Dimension tolerance is +/- 0.75". l. An alternate dash panel has been approved for use in Spec Racer Fords. The dash will be furnished by Enterprises only. P/N 180100 or 180101."
slowerEP BMW Z3 2.5L intake restrictor reduced from 58mm to 56mm flat plate.
As printed in Fastrack
Effective 4/1/2023 In EP Spec Line BMW Z3 2.5L, change Notes as follows: "58 56mm Flat Plate Intake Restrictor is required with both stock or alternate throttle body."
wordingSTU Mazda BP5A classified at 1839 cc maximum displacement, 2023-04-01.
As printed in Fastrack
In STU Spec lines, classify Mazda BP5A as follows: STU Maximum Displacement (cc's) Minimum Weight Notes Mazda BP5A 1839 Chart May use engine in its entirety or specific components from the engine.
unclearSRF Hoosier wet front tire updated to P/N 46100 P185/60R13 H20 or W2.
As printed in Fastrack
In SRF, GCR section 9.1.8.D.1.X.f, change as follows: "Wet: Front – Hoosier P/N 46100 P185/60R13 H20 or W2 Rear – Hoosier P/N 46105 P205/60R13 H20 or W2 Ground clearance is 2.5" with driver as raced when P185/60R13 (H20 or W2) tires are used."
EP Correct Intake Valve Size on 1500cc Midget/Spitfire
wordingFP and HP Sprite, Midget, and Spitfire 1500 intake valve size corrected to 36.6/(1.44).
As printed in Fastrack
In FP Spec Lines, Austin-Healey Sprite Mk. I, II,III, IV MG Midget Mk I,II, III, IV & 1500, change Intake Valve Size as follows: "(I) 36.65.3/(1.44)" In FP Spec Lines, Triumph Spitfire Mk. IV & 1500, change Intake Valve Size as follows: "(I) 36.65.5/(1.440)" In HP Spec Lines, Triumph Spitfire 1500, change Intake Valve Size as follows: "(I) 36.65.5/(1.440)" In HP Spec Lines, Triumph Spitfire Mk. III & IV 1500, change Intake Valve Size as follows: "(I) 36.65.5/(1.440)"
wordingEP Triumph TR8 78-81 removes alternate front hub allowance note; stock hubs now required.
As printed in Fastrack
In the EP Spec Lines, Triumph TR8 (78-81), remove the following wording from Notes: "Alternate front hubs are allowed provided they are of the same external dimensions as stock and weigh no less than the stock hubs."
wordingSRF radiator rule clarified: P/N 480466 replaceable with Automotive P/N 1R698, CU698 or manufacturer equivalent with documentation.
As printed in Fastrack
In SRF, GCR section 9.1.8.D.1.V.j, change as follows: "Radiator - Enterprises new style P/N 480465 (requires baffle P/N 480464) or P/N 480466 can be used. P/N 480466, may can be replaced with Automotive P/N 1R698, CU698 or equivalent OEM manufacturer justified by one cross-reference chart equivalent, as long as the size, shape, and material are the same as the original P/N. The capacity, core thickness, etc., cannot be changed even if allowed under the above. The competitor is responsible for providing this documentation of the cross-reference P/N."
cars addedEP Porsche 944/924S combines 2.5L and 2.7L variants with new weights: 2250–2415 lbs depending on engine and year.
As printed in Fastrack
In EP Spec Lines, delete the Porsche 944/924S 2.5L (2V) (83-88) spec line entirely, and create a new spec line for Porsche 944/924S 2.5L(2V) 2.7L(2V) (83-89) as follows:
A specification table follows in the original; it is not shown here.
wordingSRF rain/brake light now requires Super Bright LEDs Inc. P/N PT-STRB-R24 with specific connector and rain light switch.
As printed in Fastrack
In SRF, GCR section 9.1.8.D.1.W.l, change as follows: "A Super Bright LEDs Inc. rain / brake light comprised of a single standard trailer oval lamp, 2-1/4 inches x 6-1/2 inches, with incandescent or LED illumination, P/N PT-STRB-R24, is required in the original roll hoop mounting location. This rule supersedes GCR section 9.3.32.B.2 effective 1/1/2024 through 12/31/2024. No changes may be made to the original 3-pin connector on the wiring harness. The secondary filament of the brake light assembly shall must be connected to a switch enabling its use as a rain light."
wordingSRF requires Super Bright LEDs P/N PT-STRB-R24 rain/brake light with strobing capability and specific wiring.
As printed in Fastrack
In SRF, GCR section 9.1.8.D.1.W.l, change as follows: "A Super Bright LEDs Inc. P/N PT-STRB-R24 (SCCA Enterprises P/N 180427A) rain / brake light, P/N PT-STRB-R24, is required in the original roll hoop mounting location. This rule supersedes GCR section 9.3.32.B.2 effective 1/1/2024 through 12/31/2024. No changes may be made to the original 3-pin connector on the wiring harness. An SCCA Enterprises P/N 1190503 Strobing Brake Light Pigtail is required. The secondary filament of the brake light assembly must be connected to a switch enabling its use as a strobing rain light. A Strobing Brake Light Kit P/N 1168003 is available, which includes the brake light and pigtail."
In EP spec line, Triumph GT6, make the following change in the Notes section: "Two (2) 1.75” auto-type carburetors @ 1970 40 lbs. Three (3) Weber 40 DCOE on IR manifold with 28mm chokes @ 1990 lbs. Laycock overdrive, May use 5 speed gearbox w/o overdrive. Three (3) Weber 40mm DCOE w/28mm venturi on individual runner manifold @ 2020 lb."
otherSRF adds brake duct and pedal extension rules, rear shift cable clamp option, camber limit to 5.0°, radiator opening height 3.5" ±0.5", and P2 engine restrictor changes.
As printed in Fastrack
In SRF, GCR section 9.1.8.D.1.H, add the following: "NO MODIFICATIONS ALLOWED. Front brake ducts are required, attached to the openings in the lower radiator baffles, any flexible 4" duct material allowed, installed length minimum 12" maximum 36" in length. Must be securely fastened, Bracket Part # P/N 800368 can be used. Shall Must serve no other purpose. An extension may be welded to the side of the throttle pedal to improve heel-and-toe braking. Master cylinder casting / location must be used as delivered on P/N 180110 Pedal Mounting support. Aeroquip style -3 braided stainless flex lines only, must attach to all brake components without modification. Brake pad "anti-rattle" clips must be removed." In SRF, GCR section 9.1.8.D.1.V, add the following:
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"ii. Rear SADEV shift cable aluminum two-piece style clamp may be used. The P/N WM302007A clamp must serve no other purpose." In SRF, GCR section 9.1.8.D.1.X.k, add the following: "Negative camber shall must not exceed 5.0 degrees absolute maximum front and rear." In SRF, GCR section 9.1.8.D.1.AA.b, add the following: "2. Height of the radiator opening vertical surface 3 1/2“ +/- 1/2"." P2 Engine Table B.1 2008 and older Stock Suzuki, Yamaha, Honda, BMW 38.5mm P2 Engine Table B.2 Not required P2 Engine Table B.3 38.5mm Modified Engine 950 lbs. 1005cc max P2 Engine Table B.1 2008 and older 37mm P2 Engine Table B.2 Not required P2 Engine Table B.3 39mm Stock Engine 1050 lbs.
fasterEP Honda S2000 fuel injected throttle body inside diameter increases from 62mm to 64mm.
As printed in Fastrack
In EP spec line, Honda S2000, make the following changes to its spec line: Fuel Injected Equipped Throttle Body Inside Diameter: "62 64" Notes: "Comp. Ratio limited to 12.0:1. Valve lift limited to .500”. An adaptor plate can be used to mount the 62mm throttle body from '00-05 to the '06-09 intake manifold. The adaptor plate can be no more than 1.25" thick, and its bore must not exceed the "Fuel Injected Equipped Throttle Body Inside Diameter" maximum spec of 64mm."
wordingEP Triumph TR8 dry sump allowance moved from carburetor line to notes section.
As printed in Fastrack
In EP spec line, Triumph TR8 (78-81), move the "Dry sump allowed" wording to the appropriate location as follows: Carburetor. No. & Type: “Zenith Stromberg carbs or fuel injection. Dry sump is allowed.” Notes: “Comp. Ratio limited to 12.0:1, Valve lift limited to .500”. Dry sump is allowed.”
wordingSTL and STU power steering rules clarified to permit electric-assisted and hydraulic-assisted steering systems.
As printed in Fastrack
In GCR, Section 9.1.4.M.16., change as follows: "Power steering may be modified in any of the following ways: a. disconnected , pump, belt, pulley, and hoses may be removed. Hoses may also be looped. Steering rack or box may be modified internally to work without pump. b. an OEM manual steering rack for that model may be fitted c. an electric power steering pump may be fitted d. an OEM electric-assisted steering system may be used or any column mounted electric steering assist may be used e. an OEM hydraulic-assisted steering system may be used"
wordingSTU Mini Cooper S SC: alternate LEAP OMICRON hood scoop LEP-OMICRON3 permitted.
As printed in Fastrack
In STU Spec Lines, Mini Cooper S SC with Minimum Weight 1900 and 2100, add to Notes: "Alternate LEAP OMICRON hood scoop part # LEP-OMICRON3 is permitted."
In HP Spec Lines, delete the following redundant spec lines in their entirety: Spec line #10 - VW Rabbit Cabriolet 1780 Spec line #3 - VW Scirocco 1588 Spec line #4 - VW Scirocco 1780 (8-valve) (83-88) Spec line #5 - VW Scirocco 1588
wordingEP Mazda RX-8 (04-11) alternate spec line removed; one primary line remains.
As printed in Fastrack
Spec Lines, make the following changes to the two Mazda RX-8 spec lines. Remove spec line entirely: Mazda RX-8 (04-11) Remove the wording "alternate": Mazda RX-8 (04-11)(alternate) Spec Mazda (SM/SMX) None.
fasterSTU RWD turbo cars no longer required to reduce restrictor by 1 mm from table.
As printed in Fastrack
In GCR, Section 9.1.4.1.H.3 - Inlet Restrictor (mm) Minimum Weight (lbs) table, change as follows: "RWD cars must reduce restrictor 1 mm from this table"
SRF3 Update Rain Tire Rule and Hoosier Decal Placement
slowerSRF wet tires: P185/60R13 H20/W2 option removed; P185/65R13 W2 front now required with P205/60R13 W2 rear.
As printed in Fastrack
In SRF, GCR section 9.1.8.D.1.X.f, change as follows: "Wet: Front – Hoosier P/N 46100 P185/60R13 H20 or W2 Rear – Hoosier P/N 46105 P205/60R13 H20 or W2 Ground clearance is 2.5” with driver as raced when P185/60R13 (H20 or W2) tires are used. OR Front – Hoosier P/N 46101 P185/65R13 W2 Rear – Hoosier P/N 46105 P205/60R13 W2
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1. It is forbidden to regroove tires. 2. The use of tire warmers or cooling methods other than natural air convection or conduction is prohibited. The penalty for violation will be the loss of qualifying times and/or the disqualification of race results. 3. Hoosier SRF/SRF3 Decal Placement: Four (4) "Hoosier" decals are required in the following locations: Two (2) 11" X 3" decals on the vertical plane of the front nose to the outside of the cooling opening on each side and two (2) 18" X 5" decals, one on each side of the engine cover or above the rear wheel openings on the vertical plane. Hoosier decals are available, free of charge, from all Hoosier tire distributors including SCCA Enterprises."
SRF3 Update to Letter 36619 with new Hoosier Contingency Decal Info
wordingSRF Hoosier decal requirement reduced from four decals in specific locations to three decals with simpler placement rules.
As printed in Fastrack
In SRF, GCR section 9.1.8.D.1.X.f.3, change as follows: "Four (4) "Hoosier" decals are required in the following locations: Two (2) 11" X 3" decals on the vertical plane of the front nose to the outside of the cooling opening on each side and two (2) 18" X 5" decals, one on each side of the engine cover or above the rear wheel openings on the vertical plane. Hoosier decals are available, free of charge, from all Hoosier tire distributors including SCCA Enterprises Per Hoosier's contingency program, three (3) decals are required to qualify for contingency awards. One (1) decal must be located on each side of the car and one (1) decal must be visible on the front."
slowerSRF brake rotor minimum thickness increases from 12.20mm to 13.25mm, Wilwood vented rotor P/N 800065.
As printed in Fastrack
In SRF, GCR section 9.1.8.D.1.X.g, change as follows: "Brakes: Hawk Blue 9012 pads P/N 801993 must be used. Wilwood vented rotor P/N 800065 shall must be used as delivered with no machining of any kind. Minimum thickness 12.20mm (0.481”) 13.25mm (0.522”)."
wordingSRF3 Hoosier logo placement changes from four decals to three decals in different locations.
As printed in Fastrack
In SRF, GCR section 9.1.8.D.2.B, change as follows: "Mandatory identification: "SRF3" near the side car numbers. "Hoosier" logo (4) on both sides front lower outer corners of the nose and each side of the tail. Three (3) "Hoosier" logos, one (1) on each side of the car and one (1) on the center front of the car."
fasterHP Sprite and Midget 1275cc and 1098cc Level 2 compression ratio raised to 12.0:1.
As printed in Fastrack
In HP Spec Lines, Austin-Healey Sprite MkI, II, III, IV MG Midget (ALL) - Level 2 - 1275cc, change Notes as follows: "(Effective 11/1/2024) Compression ratio limited to 11 12.0:1" In HP Spec Lines, Austin-Healey Sprite MkI, II, III, IV MG Midget (ALL) - Level 2 - 1098cc, change Notes as follows: "(Effective 11/1/2024) Compression ratio limited to 11 12.0:1"
slowerSTU Mini Cooper S SC 1900 restricts to 2.565 diameter pulley; 2100 allows 2.285 diameter pulley.
As printed in Fastrack
In STU Spec Lines, Mini Cooper S SC, add to notes: 1900: "Stock supercharger pulley. 2.565 diameter." 2100: "JCW Pulley permitted. May run a 2.285 diameter pulley."
slowerEP Triumph GT6 switches to three Weber 40 DCOE carbs with 28mm chokes, weight rises 50 lbs to 1990.
As printed in Fastrack
In EP Spec Lines, make the following changes in the "Triumph GT6" spec line: Carburetor No. & Type: (2): "1.5” 1.75" Auto-type carburetor(s)" Notes: "Two (2) 1.75” auto-type carburetors @ 1940 lbs. Three (3) Weber 40 DCOE on IR manifold with 28mm chokes @ 1990 lbs. Laycock overdrive, May use 5 speed gearbox w/o overdrive."
STU Request to Remove Miata Hubs from General category
wordingSTL/STU: 90-05 Mazda Miata alternate front wheel hubs moved from General to specific part approval.
As printed in Fastrack
In GCR, Section 9.1.4.M.18., change as follows: "18. Allow alternate front wheel front hubs, Mazda Motorsports Development Part #0000-04-5HUB-S1, for the 90-05 Mazda Miata: Mazda Motorsports Development Part #0000-04-5HUB-S1."
slowerSTU BMW N54/N55 turbo inlet restrictors now required per GCR definition; turbo swapping prohibited.
As printed in Fastrack
"Turbo inlet restrictors designed per GCR Appendix F Technical Glossary definition of “Turbo Inlet Restrictor” may be required; see table 9.1.4.1.H.h.2 3. Swapping of turbochargers between engine makes and models is prohibited. Supercharged cars may be approved on a case-by-case basis; twin turbo engines are allowed on a case-by-case basis only. Contact the Road Racing Technical Office for details. Twin turbo engines may be converted to single turbo using one of the allowed alternate turbos (see 9.1.4.1.H.3 2). Aftermarket turbocharger and supercharger kits will be allowed on a case-by-case basis.
slowerSTU GT3 TCR gains 275-width tire option with 100 lb weight penalty, but not in A compound.
As printed in Fastrack
In STU, Table C, GT3 TCR, add to Notes the following: "May run DOT approved tire with maximum section width of 275 with 100 pound weight adder. May not run A compound with 275."
engineSTU BMW N54/N55 3.0L classified at Chart +3% minimum weight; N54 twin turbo not allowed.
As printed in Fastrack
In STU Spec Lines, Table A, classify BMW N54/N55 as follows: STU Maximum Displacement (cc's) Minimum Weight Notes BMW N54/N55 3.0 Chart +3% (DI) Short blocks, heads, and intakes may be freely swapped within these engine designations. N54 twin turbo not allowed
fasterHP Ford Festiva 88-93 minimum weight drops to 1600 lbs, variants to 1640 and 1680 lbs; compression ratio raised to 11.0:1.
As printed in Fastrack
In HP Spec Lines "Ford Festiva (88-93)" change as follows: Weight: "1700 1600 *1743 1640 **1785 1680" Notes: "Compression ratio limited to 10.5 11.0:1. Valve lift limited to .450”."
wordingSRF drivers with disabilities may modify seat and controls for safety and comfort with approval and logbook notation.
As printed in Fastrack
In SRF, GCR section 9.1.8.D.1.D, add the following: "f. Driver Safety and Comfort modifications to seat and controls for drivers with disabilities may be made only by approval. These modifications must be reported to SCCA Enterprises and noted in the car logbook. The modifications are approved only for the noted driver with disabilities. If the car is used by or sold to another driver, it must be returned to the previous standard configuration."
wordingSTU wheel width rules clarified: cars ≤2,850 lbs max 8 inches, cars >2,850 lbs max 9 inches.
As printed in Fastrack
In GCR, Section 9.1.4.1.F.1., change as follows: "Wheels may not exceed 18 inches in diameter. or 8.0 inches in width for vehicles 2950 lbs. and under minimum allowed race weight. Vehicles over 2850 minimum allowed race weight may use a 9 inch wide wheel. Cars equal to or less than 2,850 lbs. minimum allowed race weight may not use wheels wider than 8 inches. Cars greater than 2,850 lbs. minimum allowed race weight may not use wheels wider than 9 inches."
fasterSTU Spec Line GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tire options clarified with weight adjustments.
As printed in Fastrack
In STU Spec Line, Table C: STU-GT3U, change as follows: Minimum Weight: “Current GT3 race weight plus 250 225 pounds” Notes: "DOT approved tire with maximum section width of 245. GT3 cars base wheel is a maximum of 15”x9”. 18”x9” wheels allowd with a 3% weight addition. GT3 cars utilizing 15”x7” wheels are limited to a maximum section width of 225 with a 25 pound weight reduction" "All GT3U (Majors and Runoffs) cars using up to 15"x7" wheels limited to 225 section width tires shall run at current GT3 race weight plus 225lbs. All Gt3U cars shall run a DOT approved tire with a maximum section width of 245. GT3U cars are allowed optional 15"x9" wheels with a 1.5% weight addition or up to 18"x9" wheels with a 3.0% weight addition to the total weight
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including the 225 lbs."
EP Base Weight Adjustment for H-Production X1/9 Spec Lines
unclearSTU 2.8-3.2L N/A engines now allow 245 max tire width; over 3150 lbs may run 275 with 2% weight penalty.
As printed in Fastrack
In GCR, Section 9.1.4.G.1, add the following: "A maximum section width of 245 is permitted. Cars over 3150 lbs. may run a 275 tire with a 2% weight adder."
cars addedSTU Honda JDM H23a added, 2259cc displacement, minimum weight per Chart, must meet ST engine regulations.
As printed in Fastrack
In STU, Table B, classify Honda JDM H23a as follows: STU Maximum Displacement (cc's) Minimum Weight Notes Honda JDM H23a 2259 Chart Must meet all ST engine regulations.
slowerSTU-TCR tire width increases to 275 with weight adder raised from 100 to 150 pounds.
As printed in Fastrack
In STU Spec Lines, Table C: STU-GT3U, GT3-TCR, change as follows: Remove the current TCR spec line and add the TCR spec lines from GT3 that are being removed, adding the below to the notes. "DOT approved tire with maximum section width of 245. May run DOT approved tire with maximum section width of 275 with 100 150 pound weight adder. May not run A-compound with 275. STU-TCR spitters and side valance must comply with 9.1.4.D.3.f. STU-TCR chassis ride height must comply with 9.1.4.1.A.1."
Effective 9/1/25 in SRF, GCR section 9.1.8.D.1.V.ff, add the following: "SRF3 Oil Cooler, P/N G480503 may be used as mounted per the GEN3 Assembly Manual. No fan permitted for SRF. HD Oil Cooler kit P/N G1148500 may be used as mounted per the GEN3 Conversion Manual." Effective 9/1/25 in SRF, GCR section 9.1.8.D.X.g, change as follows: "Brakes: Hawk Blue 9012 pads P/N 801993 must be used. Wilwood vented rotor P/N 800065 must be used as delivered with no machining of any kind. Minimum thickness 13.25mm (0.522”). The Renault Alliance solid front rotors may not be used. Rubber caliper bushings may be replaced with bronze bushings P/N 1196185 or P/N 1196185. Original caliper pistons may be replaced with vented caliper piston P/N 1196184; no other modification allowed. Wilwood caliper with bracket universal fit P/N 800038
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may be used as delivered with no modification of any kind. Wilwood knock back spring (2.63 lbs.) P/N 800045 may be used as delivered with no modification of any kind; maximum of one spring per caliper. 1. Hawk Blue pads P/N 801993 only 2. Wilwood Vented Rotor P/N 800065 only, as delivered, with no machining of any kind. Minimum thickness 13.25mm (0.522") 3. Wilwood universal caliper Kit P/N 1180008 as delivered, caliper only P/N 800038; Wilwood knock back spring P/N 800045 may be used as delivered, with no machining of any kind, and only one spring per caliper 4. Renault caliper rubber bushings may be replaced with bronze bushings P/N 1196185 or P/N 1196185A 5. Renault caliper piston may be replaced with P/N 1196184 vented piston as delivered, with no machining of any kind 6. Girling .750" Master Cylinder P/N 880358 as delivered, with no machining of any kind 7. Wilwood .750" Master Cylinder P/N 880357 as delivered, with no machining of any kind 8. Tilton .750" Master Cylinder P/N 880360 as delivered, with no machining of any kind"
otherSRF3 adds HD Oil Cooler P/N G1148500 as alternative to standard cooler P/N G480503.
As printed in Fastrack
In SRF, GCR section 9.1.8.D.1.V.ff, change as follows: "SRF3 Oil Cooler, P/N G480503 or HD Oil Cooler P/N G1148500 may be used as mounted per the GEN3 Assembly Manual. No fan permitted for SRF. HD Oil Cooler kit P/N G1148500 may be used as mounted per the GEN3 Conversion Manual."
wordingEP, FP, HP throttle body inside dimensions must remain stock with +/-.25mm tolerance; butterfly dimensions stock in FP, HP only.
As printed in Fastrack
In GCR, Section 9.1.5.E., change as follows: 9.1.5.E.1.b.4: "The inside dimensions of the throttle body casting/housing (as measured at the throttle butterfly) must remain stock (tolerance of +/-.25mm), but the throttle body can otherwise be ported and polished." 9.1.5.E.2.b.4: "The inside dimensions of the throttle body casting/housing and all dimensions of the throttle butterfly must remain stock (tolerance of +/-.25mm)."
STU Non-Homologated Engine Swaps - Specifically K24A2 w/ Honda CRZ
slowerHP Volvo 142/142E gains compression ratio limit 12.0:1 and valve lift limit .425".
As printed in Fastrack
In HP Spec Lines, Volvo 142/142E P-1800 Engine, Effective 11/1/2025 add the following wording to Notes: "Comp. Ratio limited to 12.0:1. Valve lift limited to .425”."
slowerHP Mini Cooper 07-15 valve lift reduced to .390", from .450".
As printed in Fastrack
In HP Spec Lines, Mini Cooper (07-13) (includes 09-15 convertible and 12-15 Coupe), Effective 11/1/2025 make the following changes to the Notes: "Compression ratio limited to 11.0:1, Valve lift limited to .450”.390"."
wordingFP and HP Volkswagen Rabbit descriptions updated: Convertible changed to Cabriolet in FP; Cabriolet added to three HP engine variants.
As printed in Fastrack
In FP Spec Lines, make the following spec line correction: "Volkswagen Rabbit (Includes Convertible Cabriolet)" In HP Spec Lines, make the following spec line correction: "Volkswagen Rabbit 1588 (Includes Cabriolet)" "Volkswagen Rabbit 1715 (Includes Cabriolet)" "Volkswagen Rabbit 1780 (Includes Cabriolet)"
wordingEP, FP, HP: rear drum brake to disc conversion clarified; rotors solid, diameter limited to largest front rotor permitted.
As printed in Fastrack
In GCR, Section 9.1.5.E.7., change as follows: "e. Cars fitted with rear drum brakes, can convert to rear disc brakes without penalty. Note that the “Brakes Std.” and “Brakes Alt.” listings on a vehicle’s spec line do not prohibit a car that was fitted with rear drum brakes stock, from converting to rear disc brakes under this rule. When converting from rear drum brakes to rear disc brakes: 1. Rear brake rotors must be solid and can be no larger in diameter than the largest permitted front brake rotor, as defined on the vehicle’s spec line. 2. Rear calipers and mounting brackets are unrestricted but must be made of a ferrous or aluminum material. The standard and alternate brake listings on a vehicle’s specification line, does not prohibit a car that was fitted with rear drum brakes as stock
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from converting to rear disc brakes under this rule. 3. The “Brakes Std.” and “Brakes Alt.” listings on a vehicle’s spec line do not prohibit a car that was fitted with rear drum brakes as stock from converting to rear disc brakes under this rule."
slowerSTU cars over 3150 lbs lose 275-tire option with 2% weight adder.
As printed in Fastrack
In GCR, Section 9.1.4.G.1., change as follows: "A maximum section width of 245 is permitted. Cars over 3150 lbs. may run a 275 tire with a 2% weight adder."
unclearEP Triumph TR2-TR4A allows 5-speed gearbox without overdrive; removes Weber carb and weight specification.
As printed in Fastrack
In EP Spec Lines, Triumph TR2, 3, 3A, 4, 4A, TR4, TR4A, IRS, make the following change to the Notes: "Front apron assembly may be made of alternate material. Three (3) Weber 40 DCOE on IR manifold with 28mm chokes @ 1990 lbs. Laycock overdrive, may use 5 speed gearbox without overdrive."
fasterSTU Mazda MZR (LF, L3, L5) Turbo classified; Jack Spania Racing 70 mm intake manifold and Fab9 Tuning bottom-mount turbo kit approved.
As printed in Fastrack
In STU Spec Lines, Table A: Alternate Vehicle and Engine Allowances, Mazda MZR (LF, L3, L5), change Notes as follows: "Short blocks, heads, and intakes may be freely swapped within these engine designations. May use Goodwin Part # 61- 2510 or, Gato Performance Part #31972 or Jack Spania Racing 70 mm sheet-metal aluminum Intake manifold. Must use stock throttle body or Acura part number 16400-PND-A17." In STU Spec Lines, Table A: Alternate Vehicle and Engine Allowances, classify Mazda MZR (LF, L3, L5) Turbo as follows: STU Maximum Displacement (cc's) Minimum Weight Notes Mazda MZR (LF, L3, L5) Turbo
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Varies Chart Short blocks, heads, and intakes may be freely swapped within these engine designations. May use Jack Spania Racing 70 mm sheet-metal aluminum Intake manifold. Must use stock throttle body or Acura part number 16400-PND- A17. Fab9 Tuning bottom-mount turbo kit approved with one of the STU approved Turbos.
What the rules allowed changed as listed; this does not say what any particular car ran.